Source code for airflow.operators.bash_operator

# -*- coding: utf-8 -*-
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.


import os
import signal
from subprocess import Popen, STDOUT, PIPE
from tempfile import gettempdir, NamedTemporaryFile

from builtins import bytes

from airflow.exceptions import AirflowException
from airflow.models import BaseOperator
from airflow.utils.decorators import apply_defaults
from airflow.utils.file import TemporaryDirectory
from airflow.utils.operator_helpers import context_to_airflow_vars


[docs]class BashOperator(BaseOperator): r""" Execute a Bash script, command or set of commands. .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:BashOperator` :param bash_command: The command, set of commands or reference to a bash script (must be '.sh') to be executed. (templated) :type bash_command: str :param xcom_push: If xcom_push is True, the last line written to stdout will also be pushed to an XCom when the bash command completes. :type xcom_push: bool :param env: If env is not None, it must be a mapping that defines the environment variables for the new process; these are used instead of inheriting the current process environment, which is the default behavior. (templated) :type env: dict :param output_encoding: Output encoding of bash command :type output_encoding: str .. warning:: Care should be taken with "user" input or when using Jinja templates in the ``bash_command``, as this bash operator does not perform any escaping or sanitization of the command. This applies mostly to using "dag_run" conf, as that can be submitted via users in the Web UI. Most of the default template variables are not at risk. For example, do **not** do this: .. code-block:: python bash_task = BashOperator( task_id="bash_task", bash_command='echo "Here is the message: \'{{ dag_run.conf["message"] if dag_run else "" }}\'"', ) Instead, you should pass this via the ``env`` kwarg and use double-quotes inside the bash_command, as below: .. code-block:: python bash_task = BashOperator( task_id="bash_task", bash_command='echo "here is the message: \'$message\'"', env={'message': '{{ dag_run.conf["message"] if dag_run else "" }}'}, ) """
[docs] template_fields = ('bash_command', 'env')
[docs] template_ext = ('.sh', '.bash',)
[docs] ui_color = '#f0ede4'
@apply_defaults def __init__( self, bash_command, xcom_push=False, env=None, output_encoding='utf-8', *args, **kwargs): super(BashOperator, self).__init__(*args, **kwargs) self.bash_command = bash_command self.env = env self.xcom_push_flag = xcom_push self.output_encoding = output_encoding self.sub_process = None
[docs] def execute(self, context): """ Execute the bash command in a temporary directory which will be cleaned afterwards """ self.log.info("Tmp dir root location: \n %s", gettempdir()) # Prepare env for child process. env = self.env if env is None: env = os.environ.copy() airflow_context_vars = context_to_airflow_vars(context, in_env_var_format=True) self.log.debug('Exporting the following env vars:\n%s', '\n'.join(["{}={}".format(k, v) for k, v in airflow_context_vars.items()])) env.update(airflow_context_vars) self.lineage_data = self.bash_command with TemporaryDirectory(prefix='airflowtmp') as tmp_dir: with NamedTemporaryFile(dir=tmp_dir, prefix=self.task_id) as f: f.write(bytes(self.bash_command, 'utf_8')) f.flush() fname = f.name script_location = os.path.abspath(fname) self.log.info( "Temporary script location: %s", script_location ) def pre_exec(): # Restore default signal disposition and invoke setsid for sig in ('SIGPIPE', 'SIGXFZ', 'SIGXFSZ'): if hasattr(signal, sig): signal.signal(getattr(signal, sig), signal.SIG_DFL) os.setsid() self.log.info("Running command: %s", self.bash_command) self.sub_process = Popen( ['bash', fname], stdout=PIPE, stderr=STDOUT, cwd=tmp_dir, env=env, preexec_fn=pre_exec) self.log.info("Output:") line = '' for line in iter(self.sub_process.stdout.readline, b''): line = line.decode(self.output_encoding).rstrip() self.log.info(line) self.sub_process.wait() self.log.info( "Command exited with return code %s", self.sub_process.returncode ) if self.sub_process.returncode: raise AirflowException("Bash command failed") if self.xcom_push_flag: return line
[docs] def on_kill(self): self.log.info('Sending SIGTERM signal to bash process group') if self.sub_process and hasattr(self.sub_process, 'pid'): os.killpg(os.getpgid(self.sub_process.pid), signal.SIGTERM)

Was this entry helpful?